1. Field of the Invention
The invention relates to a device for processing a substrate, the device comprising a vacuum chamber and at least one sputtering chamber, which is connected to the vacuum chamber by means of a flow channel.
The invention also relates to a device for processing a substrate comprising a vacuum chamber, at least one sluice chamber and at least one sputtering chamber, whereby the device is provided with a substrate carrier which is movable within the vacuum chamber, the substrate carrier comprising a carrying table which is rotatable in one plane, by means of which a substrate to be processed can be moved from the sluice chamber to the sputtering chamber and vice versa.
The invention furthermore relates to a device for processing a substrate, the device comprising a vacuum chamber, at least one sluice chamber and at least one sputtering chamber, whereby the device is provided with a substrate carrier which is movable within the vacuum chamber, the substrate carrier comprising a carrying table which is rotatable in one plane and which is movable transversely to the plane, by means of which a substrate to be processed can be moved from the sluice chamber to the sputtering chamber and vice versa.
2. Description of the Related Art
Devices of the kind referred to in the introduction are known from European Patent EP-B1-0 136 562.
A substrate to be processed is introduced into the sputtering chamber via the vacuum chamber and coated with a relatively thin film of material, for example aluminum, by means of a sputtering deposition process. The properties of the sputtered film are partly determined by reactive residual gases present in the vacuum in the sputtering chamber. A frequently occurring residual gas is water, which in many cases reacts with the material of the film. If the material is aluminum, aluminum oxide is thereby formed in the film, which is in most cases undesirable. Aluminum oxide for example has a negative influence on the reflective properties of the aluminum film.
In order to minimize the influence of the residual gas, the ratio of a flow of particles of the desired material and of a flow of particles of the residual gas to the substrate needs to be sufficiently large. When a substrate is introduced into the vacuum chamber, air containing reactive gases such as O.sub.2 and H.sub.2 O finds its way into the vacuum chamber and when the substrate is moved from the vacuum chamber to the sputtering chamber, part of the air containing the reactive residual gases finds its way into the sputtering chamber. It has been attempted to extract the air from the vacuum chamber by means of a pump system. The sputtering chamber is in open communication with the vacuum chamber via the flow channel. The residual gases present in the sputtering chamber are led to the vacuum chamber and largely removed therefrom by means of the vacuum chamber. As the frequency at which the substrates are introduced into and removed from the vacuum chamber and the sputtering chamber increases, however, the average amount of air being supplied via the sluice chamber per time unit will also increase. This also leads to higher demands on the pump system. The amount of residual gas molecules in the film cannot be limited to the amount of residual gas molecules present in the sputtering chamber, since the sputtering chamber is in open communication with the vacuum chamber via the flow channel. The incorporation of residual gas molecules in the film to be sputtered immediately leads to a difference in the partial pressures of the residual gas in the vacuum chamber and the residual gas in the sputtering chamber, as a result of which the residual gas in the sputtering chamber is replenished by residual gas molecules from the vacuum chamber. As a result of this a large number of residual gas molecules find their way into the film, even if the volume of the sputtering chamber is relatively small.
A solution would seem to be to close the sputtering chamber during the deposition of the film. However, a so-called sputtering gas (mostly argon) is required for maintaining the gas discharge of the sputtering process, which sputtering gas must have a particular partial pressure. Atoms of the sputtering gas are enclosed in the growing film, as a result of which the sputtering gas partial pressure falls below an allowed value. In view of the relatively great and quick pressure changes it is not possible to regulate a desired sputtering gas partial pressure in a closed sputtering chamber.
With the device according to European patent EP-B1-0 136 562 a sputtering gas, argon, is used, which flows to the vacuum chamber via the sputtering chamber and via the flow channel. In such a known system the sputtering gas flux being supplied is much greater than the amount of sputtering gas flux incorporated in the film. A relatively large sputtering gas flux with a given sputtering pressure means that the effective pump rate of the pump system must be relatively great, which makes the device relatively costly.